Are Green Onions Ok on a FODMAP Diet? The Definitive Guide

According to Monash University, the green tops of green onions are low in FODMAPs, making them a safe way to get onion flavor in your cooking. But are green onions ok on a FODMAP diet entirely, or is there a catch to using this popular vegetable?

Quick Summary

The green, leafy tops of scallions are low FODMAP and safe for those with IBS, while the white bulb is high in fructans and must be avoided.

Key Points

• Low FODMAP Green Tops: The green, leafy section of green onions is low in FODMAPs and safe to eat for those with IBS.

• Avoid the White Bulb: The white bulb and pale green parts contain high levels of fructans and should be discarded.

• Monash Verified Portions: According to Monash University, a generous serving of the green tops (up to 1.5 cups or 75g) is low FODMAP.

• Fructans Are Water-Soluble: Cooking with the white bulb and then removing it is not effective, as the fructans will have leached into the dish.

• Flavorful Substitute: Use the chopped green tops as a garnish or sauté them in low-FODMAP oil to add onion flavor to your meals.

• Regrow from Scraps: You can easily regrow the green tops from the white bulb by placing the roots in water, ensuring a constant supply.

Understanding FODMAPs and Onion Sensitivities

Before diving into the specifics of green onions, it's helpful to understand why traditional onions are often problematic on a low FODMAP diet. FODMAPs are short-chain carbohydrates that can be poorly absorbed in the small intestine. For individuals with Irritable Bowel Syndrome (IBS), these carbohydrates draw water into the bowel and are rapidly fermented by gut bacteria, leading to uncomfortable symptoms like bloating, gas, and abdominal pain. Regular onions, including white, yellow, and red varieties, contain a high level of fructans, a type of oligosaccharide that is a major FODMAP trigger for many. This is why they are typically eliminated during the initial phase of the diet.

What Are FODMAPs?

FODMAP is an acronym for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These are groups of fermentable carbohydrates that can trigger digestive symptoms in sensitive individuals.

• Oligosaccharides: Includes fructans (found in onions, garlic, wheat) and galacto-oligosaccharides (GOS) (found in legumes).
• Disaccharides: Includes lactose (found in dairy).
• Monosaccharides: Includes excess fructose (found in some fruits like apples and pears).
• Polyols: Includes sorbitol and mannitol (found in some fruits and vegetables).

Why Regular Onions Are High FODMAP

Regular onions are packed with fructans, a type of carbohydrate that most people cannot fully digest. When consumed, these fructans travel to the large intestine where they are fermented by gut bacteria, producing gas and causing distress in those with IBS. This makes regular onions a major trigger food on a low FODMAP diet. Fortunately, the structure of green onions offers a work-around for this flavor-limiting problem.

Are Green Onions Low FODMAP? The Critical Distinction

The answer to whether green onions are acceptable on a FODMAP diet lies in distinguishing between the different parts of the vegetable. The green, leafy tops are low in fructans, while the white bulb and lighter green parts are high in FODMAPs. This means you can get the oniony flavor you crave by using the green portion safely, as long as you discard the high-FODMAP bulb.

The Low-FODMAP Green Tops

Monash University, the leading authority on FODMAP research, has tested green onions (also known as scallions or spring onions) and confirmed that the green tops are low in FODMAPs. A low FODMAP serving of the green, leafy part is generous, with Monash allowing up to 1.5 cups (75g) per serving. The green tops provide a fresh, mild onion flavor that can be used in a variety of dishes without triggering symptoms for most people with IBS.

The High-FODMAP White Bulb

Conversely, the white bulb and the pale green section where it meets the stem are high in fructans and should be avoided during the elimination phase of the diet. It is important to note that since fructans are water-soluble, cooking the whole green onion and removing the bulb afterwards will not eliminate the FODMAPs, as they will have already leached into your food. This makes proper preparation essential for symptom management.

How to Prepare and Use Low-FODMAP Green Onions

Utilizing the low-FODMAP green tops is a simple process that can add back the vital onion flavor many miss. The first step is to carefully separate the green leaves from the white bulb. You can either use them immediately or store them for later use. Once prepped, they are incredibly versatile.

Cooking and Serving Tips

• Garnish: Chop the green tops finely and sprinkle them over soups, stews, roasted vegetables, or salads just before serving for a burst of fresh flavor.
• Sauté: Sauté the chopped green tops in a low-FODMAP oil, such as garlic-infused olive oil, to create a flavorful base for stir-fries, sauces, or rice dishes.
• Eggs: Add sliced green onion tops to scrambled eggs or omelets for a savory and satisfying breakfast.
• Freezing: For long-term storage, chop the green tops and freeze them in a sealed bag. Frozen green onions are perfect for adding directly to cooked dishes.

How to Regrow Green Onions

To minimize waste and maintain a steady supply, you can regrow the green tops from the leftover white bulbs.

1. Cut: After using the green tops, save the white bulbs with the roots attached.
2. Place: Stand the bulbs root-side down in a small glass with about 1-2 inches of water.
3. Grow: Place the glass on a sunny windowsill. Change the water every few days to prevent cloudiness.
4. Harvest: The green shoots will regrow within a couple of weeks, providing a fresh supply.

Comparison: Green Onion Green Tops vs. White Bulbs

To clarify the differences, here is a breakdown of the two parts of a green onion in the context of a low FODMAP diet:

Feature	Green Tops (Leaves)	White Bulb (Root End)
FODMAP Content	Low	High (specifically fructans)
FODMAP Source	No significant FODMAPs detected by Monash	Fructans, a major FODMAP trigger
Usage on Low FODMAP Diet	Yes, safe to consume in moderate-to-large amounts	No, should be avoided during the elimination phase
Flavor Profile	Mild, fresh, oniony taste	Strong, more pungent onion flavor
Cooking Application	Raw or cooked; added near the end of cooking	Must be discarded or used for regrowing

Conclusion: Smart Seasoning for FODMAP Management

For those following a low FODMAP diet, green onions are a true culinary asset. By making the simple but crucial distinction between the safe green tops and the high-FODMAP white bulbs, you can enjoy a delicious onion flavor without risking digestive discomfort. With a little care in preparation, green onions offer a versatile and flavorful ingredient that can be used in countless dishes, helping to make the low FODMAP diet a more satisfying and less restrictive experience. Always remember to consult the Monash University FODMAP app for the most current serving size recommendations and to confirm your food choices. Monash FODMAP App Link

Low-FODMAP Onion-Flavor Alternatives

Beyond green onion tops, several other low-FODMAP options can provide an onion-like flavor in your cooking. These can be used in combination with or in place of green onions to add variety to your meals.

• Chives: A member of the onion family, chives offer a delicate, mild onion flavor and are low FODMAP. They are best used as a garnish or added to dishes at the end of cooking.
• Leek Greens: Similar to green onions, the dark green leafy tops of leeks are low FODMAP, while the white bulb is high in fructans. The green leaves have a mild, oniony flavor and can be used in cooked dishes.
• Garlic-Infused Oil: Since fructans are not oil-soluble, infusing oil with garlic or onion provides flavor without the FODMAPs. This is an excellent option for flavoring a wide range of dishes.
• Asafoetida: Also known as 'hing,' this pungent spice is used in Indian cooking to mimic the flavor of onions and garlic. A small pinch is often enough to add depth to a dish.
• FODMAP-Friendly Onion Replacements: Some specialized products are available that mimic onion flavor without the FODMAP content.

By exploring these various options, you can continue to create delicious and flavorful meals while successfully managing your FODMAP intake.

Frequently Asked Questions

Can I eat the entire green onion on a low FODMAP diet?

No, you should not eat the entire green onion. Only the green, leafy tops are low in FODMAPs. The white bulb is high in fructans and should be discarded or used for regrowing.

How can I tell the difference between the low FODMAP and high FODMAP parts?

The division is at the point where the dark green leaves start to fade into the lighter green and white bulb. Use only the dark green portion and discard the rest.

Is it safe to cook with the whole green onion and then remove the white part?

No, this method is not safe on a low FODMAP diet. Fructans are water-soluble and will leach out of the white bulb into your food during the cooking process, contaminating the dish with high FODMAPs.

How much of the green onion tops can I eat?

Monash University has tested and verified that up to 1.5 cups (75g) of the green tops is a safe low FODMAP serving size for most people.

Can I use green onion powder instead?

Most commercial green onion or onion powders are made from the high-FODMAP bulb. It is important to check if a specific product is certified low FODMAP before use.

Are chives and leek greens also low FODMAP?

Yes, chives are a low FODMAP option for onion flavor. Similarly, the green leafy part of a leek is also low FODMAP, while the white bulb is not.

What if I accidentally eat a small amount of the white bulb?

For many, a small amount may not cause symptoms. However, if you are highly sensitive, it could trigger a reaction. It is best to avoid it completely during the strict elimination phase and test your personal tolerance during reintroduction.